1. Field of the Invention
The present invention relates to medical devices and, in particular, to an improved knee brace hinge.
2. Description of the Related Art
Many types of braces have been made available for the support of body joints which have become weakened as a result of sports activity, accident, deterioration due to age, or disease. Braces for the knee are designed primarily to provide support while enabling the knee to function during normal activity.
Knee braces are often utilized by people who have suffered a knee injury and require some means of protection against further aggravation of the knee during rehabilitation. A knee brace can limit the amount of damage to an injured knee by providing the patient with adequate knee stabilization and control. Stabilization and control is achieved in such a manner as to permit the patient relative freedom in the normal use of the knee joint while, at the same time, permitting control over the joint so as to optimize healing.
In addition, knee braces are often employed by a person having previously suffered a knee injury who wishes to actively participate in strenuous and demanding physical activity. In such cases where the person seeks knee support in furtherance of activities involving heavy running or sprinting, it is extremely advantageous to design a knee brace which most accurately simulates the true motions of the anatomical knee joint. This will minimize the leg forces required to overcome mismatched motions and generally increase comfort levels.
Knee braces generally serve two purposes. Firstly, the brace has to support the knee at all times, but especially during movement. Secondly, the brace should limit knee movements in flexion or extension within limits beyond which injury to the knee may occur. Further, movements are confined to the varus/valgus plane.
Flexion is defined as flexing of the knee from the extended position to a position where the foot and ankle is bent towards the thigh. Extension is defined as being the opposite movement. An extended leg is normally straight with virtually no bending at the knee joint.
Knee braces for providing support for the knee of a person are well known in the art. Such braces generally include a tibial shell which is constructed so as to be closely configured to the shape of the lower leg and a femoral shell which is constructed so as to be closely configured to the shape of the thigh area of the leg. The two shells are secured to their respective areas on the leg and are interconnected by some type of mechanism so as to pivot relative to each other as the knee is bent. The mechanism is usually a pair of hinge joints, one on each side of the knee brace, with the tibial shell usually being attached to the lower part of each one of the two knee joints and the femoral shell usually being attached to the upper part of each one of the two hinge joints.
Often, a person will wear knee braces bilaterally. When wearing double upright rigid knee braces bilaterally, the medial hinges often interfere with one another. The hinges sometimes lock together, causing the knee brace wearer to fall or injure himself. This problem is evident during normal walking and running, but becomes pronounced in activities such as snow skiing or motocross.
Therefore, there is a need for an improved knee brace which prevents interference and/or locking between the medial hinges.